Buying a new watch strap seems simple, until you discover there isn’t just one watch strap size. The right size depends on your watch case, and a strap that’s even slightly off will either sit loose or won’t fit between the lugs at all. Below you’ll find how to work out the right watch strap size in a few steps, how to fit a NATO strap, and what the difference is between leather, NATO and an Apple Watch band.
How do I know which watch strap size I need?
The most important measurement is the lug width: the distance between the two lugs (the protrusions on either side of the case) that the strap attaches to. This is always given in millimetres and is usually between 14 and 24mm, with 18, 20 and 22mm being the most common sizes.
You can find this measurement in two ways:
- On your old strap. Turn the strap over: the inside is often stamped with a number, for example “20mm”.
- Measure it yourself. Place a ruler straight between the two lugs and measure the distance in millimetres. Always round to the nearest even number.
Besides the lug width (A), a few other measurements determine whether a strap fits well:
- Buckle width (B): the width at the buckle end of the strap. If you want to reuse your original buckle, this needs to match.
- Strap length (C + D): the length of the long and short sections of the strap, often given together as, for example, “120/80”.
- Tapered (E): the difference between the lug width and the buckle width, for straps that narrow towards the buckle.
Fitting a NATO strap: step by step
A NATO strap is mounted slightly differently from a regular strap: it runs all the way around the case, so your watch stays on even if a spring bar breaks. Here’s how to fit one:
- Pass the strap between the spring bar and the case, on the side opposite the buckle.
- Pull the strap tight and thread the loose end through the buckle.
- Is your strap too thick to fit between the spring bar and the case? Position the strap first before putting the spring bars back in.
- Pass the remaining section of strap through the other spring bar, on the buckle side.
- Pull everything tight and secure it in the hole you want.
Leather strap or NATO strap: which suits you?
A leather strap looks classic and neat, the first choice for a dress watch or the office. It does need some care: keep it away from water and condition it occasionally, or the leather will start to crack.
A NATO strap (nylon) is sporty, quick to swap, and holds up well against water and sweat. Exactly why it’s popular for watches you wear every day or take into the water.
Browse our full range of NATO straps or leather straps in store.
Apple Watch band? Check the connector, not the size in mm
Sizing works differently for an Apple Watch. Instead of a lug width in millimetres, you choose by case size: 38, 40, 41, 42, 44, 45 or 49mm, depending on your model. The band’s connector needs to match that case size, not a separate mm measurement like a traditional watch.
Not sure about your Apple Watch size? Check the case size on the back of your watch, or browse our range of Apple Watch bands.
Couldn’t find the right size? We’ll make one to measure
Do you have an unusual lug width, a watch that’s no longer in production, or do you just want a strap you won’t find anywhere else? At Watchme Amsterdam we make watch straps to measure: choose your own leather, colour and finish, made to fit your watch exactly.
Still not sure about the right size, or just want to talk it through? Drop by the store or get in touch, and we’ll measure it together. Also check out our made-to-measure watch straps service for the options.
